B1131

DTC B1131: Starter setting circuit fail

CAUTION:

- Use caution that the cooling fan becomes activated when the forced power supply output of scan tool MB991958 is performed while the ECM connector is disconnected. (Fail-safe for ETACS-ECU)
- When replacing the ECU, always check that the communication circuit is normal.

DIAGNOSTIC FUNCTION

When a short circuit (short to power supply, short to ground) of starter setting circuit system is detected, OSS-ECU sets the DTC B1131. At the same time, OSS-ECU displays the power supply system error warning screen to the multi information display of the combination meter, and flashes the indicator of engine switch in orange.

DTC SET CONDITION

Check Conditions

- After OSS-ECU activation
Judgment Criterion

- When the following conditions are met:
1. When the starter setting signal is ON, the starter setting circuit voltage is less than 1.5 V.
2. When the starter setting signal is OFF, the circuit voltage is 3.5 V or more.

TROUBLESHOOTING HINTS

- Damaged wiring harness or connector (short to ground or short to power supply in STO line or STOE line)
- Malfunction of OSS-ECU
- ETACS-ECU malfunction
- Malfunction of ECM


DIAGNOSIS

STEP 1. Check of short circuit in STO line between OSS-ECU connector and ETACS-ECU connector

Q. Is the check result normal?

YES Go to Step 2
NO Repair the connector(s) or wiring harness.
STEP 2. Check of short circuit in STOE line between ETACS-ECU connector and ECM connector

Q. Is the check result normal?

YES Go to Step 3
NO Repair the connector(s) or wiring harness.
STEP 3. Voltage measurement at ECM connector (STOE terminal)

(1)Disconnect the ECM connector, and measure at the wiring harness side.

(2)Using the scan tool MB991958, set the forced power supply output to other than
"IG-ST" (Refer to forced power supply output procedure Programming and Relearning).

(3)Measure the voltage between the ECM connector (STOE terminal) and body ground.
OK: 1 V or less


(4)Using the scan tool MB991958, set the forced power supply output to "IG-ST" (Refer to forced power supply output procedure Programming and Relearning).

(5)Measure the voltage between the ECM connector (STOE terminal) and body ground.
OK: Battery voltage


Q. Is the check result normal?

YES Go to Step 4
NO
Go to Step 5

STEP 4. Using scan tool MB991958, check data list.

Check the OSS-ECU data list.

(1)Disconnect the ECM connector.

(2)Using the scan tool MB991958, perform the forced power supply output.





OK: Depending on the state of forced power supply output, the display is turned ON/OFF.


Q. Is the check result normal?

YES Replace the ECM and register the VIN and key codes Testing and Inspection).
NO Replace the OSS-ECU and register the VIN (Refer to Programming and Relearning).
STEP 5. Voltage measurement at ETACS-ECU connector (STOE terminal)

(1)Measure the ETACS-ECU connector side by backprobing.

(2)Using the scan tool MB991958, set the forced power supply output to other than
"IG-ST" (Refer to forced power supply output procedure Programming and Relearning).

(3)Measure the voltage between the ETACS-ECU connector (STOE terminal) and body ground.
OK: 1 V or less


(4)Using the scan tool MB991958, set the forced power supply output to "IG-ST" (Refer to forced power supply output procedure Programming and Relearning).

(5)Measure the voltage between the ETACS-ECU connector (STOE terminal) and body ground.
OK: Battery voltage


Q. Is the check result normal?

YES Go to Step 6
NO Replace the OSS-ECU and register the VIN (Refer to Programming and Relearning).
Then go to Step 6
STEP 6. Check whether the DTC is reset.

Q. Is the DTC set?

YES Replace the ETACS-ECU.
NO Intermittent malfunction is suspected How to Cope With Intermittent Malfunctions).